Perched on top of a shoe shelf at the entrance of Veriff’s headquarters in Tallinn, Estonia, is a sign of a cartoon unicorn that reads “Welcome to Unicorn Land!”, serving as a reminder of the identity verification company’s rise from a local start-up to a valuation of US$1.5 billion in seven years.Veriff, which boasts clients including PayPal, Bumble and Visa, was founded by Kaarel Kotkas in 2015. It is one of at least 10 unicorn companies – privately held start-ups valued at more than US$1...